Answer:
The energy stored in the capacitor quadruples its original value.
Explanation:
The energy stored in a capacitor is given by the equation

where
C is the capacitance
V is the voltage across the plates
The capacitance, C, depends only on the properties of the capacitor, so it does not change when the voltage applied is changed.
Instead, in this problem the voltage applied is doubled:
V' = 2V
So the new energy stored is

so, the energy stored has quadrupled.
Answer:
require a medium to propagate
Explanation:
this is because electromagnetic waves can travel through vacuum at the speed of 3.0 x 10^8 m/s
because they don't need particles to transfer energy
hope this helps
Answer:
a
Explanation:
the color reflected is the color you see
You oughtta be able to do this one.
The "efficiency" is just the portion of the input work that
comes out in a useful form.
If the efficiency is 70%, that tells you that however much work
you put INto the machine, the machine will do 70% of that much
work for you at the output side.
Put 20,000 J in ... out comes (0.70) x (20,000 J) = 14,000 J .
What happens to the other 30% of the work you put into it ?
It turns into HEAT. That's why machines always have to be
cooled somehow while they're running.
Answer:
The charge flows through a point in the circuit during the change is 0.044 C.
Explanation:
Given that,
Number of turns in the copper wire, N = 200
Area of cross section, 
Resistance of the circuit, R = 118 ohms
If an externally applied uniform longitudinal magnetic filed in the core changes from 1.65 T in one direction to 1.65 T in the opposite direction.
We need to find the charge flows through a point in the circuit during the change. Due to change in magnetic field an emf is induced in it. It is given by :

Using Ohm's law :


Electric current is equal to the rate of change of electric charge. So,

So, the charge flows through a point in the circuit during the change is 0.044 C.